The present invention relates to a window regulator having an improved crank assembly for a motor vehicle window. The crank assembly uses a roller-ramp principle to lock the crank assembly against backdrive displacement when the window is directly engaged and has a downward force applied thereto. This assembly is relatively inexpensive and more effective than previous designs. It also reduces free play of the window and between the drive and driven members in the device.
It has been well established for automobile window regulators to employ a spring clutch type mechanism for coupling the window crank handle to the vehicle window. An example of this type of arrangement is illustrated in U.S. Pat. No. 1,997,646. While these arrangements have been effective, they permit an undesirable amount of displacement or free play upon manual engagement and backdriven movement of the window itself towards a raised or lowered direction. Such backdriven movement may even manifest itself as slight movement in the input crank handle. It is an object of the present invention to reduce or substantially eliminate such backdriven movement. It is also an object of the present invention to reduce the number of parts required and provide a more cost-effective assembly.
In accordance with the objects of the present invention, there is provided a window regulator assembly comprising a window panel, a track, a slider member, a slider moving assembly including a drive assembly and a coupling assembly. The track is constructed and arranged to guide the window panel during movement of the window panel between opened and closed positions. The slider member is constructed and arranged to be movable along the track between a first position wherein the window panel assumes the closed position and a second position wherein the window panel assumes the open position. The slider moving assembly is constructed and arranged to move the slider member between the first and second position, The coupling assembly of the slider moving assembly is constructed and arranged to couple an output movement of the drive assembly to the slider member. The drive assembly includes a drivable input structure and a driven output structure, which structures are rotatable about a common axis. The coupling assembly is connected with the output structure to receive the output of the output structure, thereby enabling the coupling assembly to couple the output movement of the drive assembly to the slider member. The drivable input structure is constructed and arranged to receive an external driving force so as to be rotated about its axis. The driven output structure is driven for rotational movement about its axis by rotation of the input structure. The drive assembly includes roller and spring members disposed within a housing and constructed and arranged to prevent movement of the output structure upon predetermined external force being applied thereto via the coupling assembly. The output structure has ramp surfaces each converging toward the housing. Each of the ramp surfaces frictionally engages an associated one of the rollers, the rollers being biased by the spring members in a converging surface direction towards the converging surfaces between the ramp surfaces and the housing. The rollers are thus biased into wedging relation between the ramp surfaces and the housing. Friction between the ramp surfaces and the associated rollers during application of the predetermined external force to the output structure urges rolling movement of the rollers in the converging surface direction and into further wedging relation between the ramp surfaces and the housing. The wedging relation of the rollers between the ramp surfaces and the housing prevents movement of the output structure upon application of the predetermined external force being applied thereto. The input structure is rotatable to engage the rollers upon application of the external driving force and thereby move the rollers against the bias of the spring members and away from the converging surface direction, the rollers thus being moved out of the wedging relation between the ramp surfaces and the housing so that continued driven movement of the input structure after engagement thereof with the rollers is received by the output structure so that the output structure is thereby driven to move the slider member and thus the window panel via the coupling assembly.